Biology subjects

Gilch, S.

Publications and source records attributed to Gilch, S..

3 recordsLinked to original sources

bioRxiv2022

Shift of the insoluble content of the proteome in aging mouse brain

Aging and protein aggregation diseases are inextricably linked. During aging, cellular response to unfolded proteins are believed to decline which results in diminished protein homeostasis (proteostasis). Indeed, in model organisms, such as C. elegans, proteostatic decline with age has even been linked to the onset of aggregation of proteins in wild-type animals. However, this correlation has not been extensively characterized in aging mammals. To reveal the insoluble portion of the proteome, we analyzed the detergent-insoluble fraction of mouse brain tissues after high-speed centrifugation by quantitative mass spectrometry. We identified a cohort of 171 proteins enriched in the pellet fraction of older mice including the alpha crystallin small heat shock protein. We then performed a meta-analysis to compare features among distinct groups of detergent-insoluble proteins reported in the literature. Surprisingly, our analysis revealed that features associated with proteins found in the pellet fraction differ depending on the ages of the mice. In general, insoluble proteins from young models (<15 weeks) were more likely to be RNA-binding, more disordered and more likely to be found in membraneless organelles. These traits become less prominent with age within the combined dataset, as proteins with more structure enter the pellet fraction. This analysis suggests that age-related changes to proteome organization lead a specific group of proteins to enter the pellet fraction as a result of loss of proteostasis.

cell biology↗

bioRxiv2022

Transmission of Cervid Prions to Humanized Mice Demonstrates the Zoonotic Potential of CWD

Prions cause infectious and fatal neurodegenerative diseases in mammals. Chronic wasting disease (CWD), a prion disease of cervids, spreads efficiently among wild and farmed animals. Potential transmission to humans of CWD is a growing concern due to its increasing prevalence. Here, we provide the strongest evidence to date supporting the zoonotic potential of CWD prions, and their probable materialization in humans using mice expressing human prion protein (PrP) as an infection model. Inoculation of these mice with deer CWD isolates resulted in atypical clinical manifestations, with prion seeding activity and efficient transmissible infectivity in the brain and, remarkably, in feces. Intriguingly, the protease-resistant PrP in the brain resembled that found in a familial human prion disease and was transmissible upon second passage. Our results are the first evidence that CWD can infect humans with a distinctive clinical presentation, signature, and tropism, and might be transmissible between humans while current diagnostic assays might fail to detect it. These findings have major implications for public health and CWD management.

neuroscience↗

bioRxiv2021

Ligands binding to the cellular prion protein induce its protective proteolytic release with therapeutic potential in neurodegenerative proteinopathies

The cellular prion protein (PrPC) is a central player in neurodegenerative diseases caused by protein misfolding, such as prion diseases or Alzheimers disease (AD). Expression levels of this GPI-anchored glycoprotein, especially at the neuronal cell surface, critically correlate with various pathomechanistic aspects underlying these diseases, such as templated misfolding (in prion diseases) and neurotoxicity and, hence, with disease progression and severity. In stark contrast to cell-associated PrPC, soluble extracellular forms or fragments of PrP are linked with neuroprotective effects, which is likely due to their ability to interfere with neurotoxic disease-associated protein conformers in the interstitial fluid. Fittingly, the endogenous proteolytic release of PrPC by the metalloprotease ADAM10 ( shedding) was characterized as a protective mechanism. Here, using a recently generated cleavage-site specific antibody, we shed new light on earlier studies by demonstrating that shed PrP (sPrP) negatively correlates with conformational conversion (in prion disease) and is markedly redistributed in murine brain in the presence of prion deposits or AD-associated amyloid plaques indicating a blocking and sequestrating activity. Importantly, we reveal that administration of certain PrP-directed antibodies and other ligands results in increased PrP shedding in cells and organotypic brain slice cultures. We also provide mechanistic and structural insight into this shedding-stimulating effect. In addition, we identified a striking exception to this, as one particular neuroprotective antibody, due to its special binding characteristics, did not cause increased shedding but rather strong surface clustering followed by fast endocytosis and degradation of PrPC. Both mechanisms may contribute to the beneficial action described for some PrP-directed antibodies/ligands and pave the way for new therapeutic strategies against devastating and currently incurable neurodegenerative diseases.

neuroscience↗